This disclosure relates to a core housing configuration for gas turbine engine that includes a gear driven fan, for example.
Gas turbine engines for commercial aircraft applications typically include an engine core housed within a core nacelle. In one type of arrangement known as a turbofan engine, the core drives a large fan upstream from the core that provides airflow into the core. A fan case and nacelle surround the fan and at least a portion of the core. A compressor section within the core compresses the air from the fan and delivers it downstream into a combustion section. One type of compressor section includes low and high pressure compressors, each with one or more stages. The compressed air is mixed with fuel and combusted in the combustion section. The products of this combustion are then delivered downstream over turbine rotors, which are rotationally driven to provide power to the engine.
The core housing is typically constructed from multiple cases that support various portions of the core. The inlet case is arranged at the front of the core to receive airflow from the fan. A low pressure compressor case is arranged behind the inlet case, and an intermediate case is arranged between the low pressure compressor case and a high pressure compressor case. Typically, the core is supported by the fan case using flow exit guide vanes that straighten the airflow as it exits a bypass flow path, which is arranged between the fan case and core nacelle. Some turbofan engines include a gear train arranged between the compressor section and the fan that is used to drive the fan at a desired speed. The gear train is typically supported by the inlet case. The gear train adds significant weight to the front of the core, which also must be carried by the flow exit guide vanes.
The flow exit guide vanes typically support the core at an axial location aft of the low pressure compressor stages. In one example, the flow exit guide vanes are axially aligned with the intermediate case. A support wall extends a significant length from the area of the flow exit guide vanes and intermediate case to the front of the inlet case to provide adequate support for the gear train. This arrangement is undesirable because it provides limited access to various engine components and makes service and assembly more difficult and costly. Further, the overall axial length of the fan case is larger than desired, which adds weight and complicates packaging. What is needed is a simplified turbine engine core front architecture that provides desired support for the gear train while decreasing weight and cost.